The conventional upright vacuum cleaner comprises a cleaner body (also known as cleaner casing or upright body), a ground brush (also generally named as suction nozzle), a dust collection chamber and a pipeline system (also known as air duct system). The ground brush is positioned at the lower part of the cleaner body and is provided with an air inlet and a motor chamber. The dust collection chamber is positioned above the ground brush and is provided with an air inlet and an air outlet. The pipeline system comprises: an air duct of the ground brush connected with the air inlet of the ground brush; a machine body air inlet duct connecting the air duct of the ground brush to the air inlet of the dust collection chamber; a machine body air outlet duct connecting the air outlet of the dust collection chamber to the motor chamber, and an exhaust pipe of the motor chamber.
In general, the conventional upright vacuum cleaner is suitable for cleaning the indoor open ground, but encounters difficulties in playing its effective role on the other positions such as hidden corners, steps and table tops. The reasons are that the dust enters the cleaner casing from the air inlet of the ground brush which is close to the ground. Except for by the air inlet of the ground brush close to the ground, the conventional upright vacuum cleaner has no other means to absorb dust.
In recent years, in order that the upright vacuum cleaner is capable of cleaning either the indoor open ground or other positions such as hidden corners, the improvements on the conventional upright vacuum cleaners are proposed, and the major improvement is the addition of a conversion valve and a suction soft pipe on the basis of conventional upright vacuum cleaner. For example, a Chinese patent CN 200410002222.3 and its patent family U.S. Pat. No. 7,213,297B2 propose such an upright vacuum cleaner with a suction soft pipe and a conversion valve, and similar products are available in the domestic market. The suction soft pipe is also known as cleaner soft pipe of which one end is connected with one air inlet of the conversion valve and the other end is used as an air suction inlet designed to clean the hidden corners or the other positions on the ground. The conversion valve is also known as pipe switching device which is positioned on the side of the cleaner body and is designed to regulate the connection and disconnection of different pipes, so that the cleaner switches between the operating state for cleaning open ground and the operating state for cleaning other positions.
As to the conversion valve of the upright vacuum cleaner as described above, there are many different structures, however each of them is provided with two air inlets and one air outlet. For the convenience of discrimination, one of the air inlets is named as the first air inlet, and the other air inlet is named as the second air inlet. The first air inlet is connected with the air duct of the ground brush via one air inlet pipe of the conversion valve which is poisoned as a whole on the outside of the ground brush and runs through the casing of the ground brush. The second air inlet is connected with the suction soft pipe. The air outlet of the conversion valve is connected with the air duct of the dust collection chamber via an air outlet pipe of the conversion valve.
When the first air inlet of the conversion valve is communicated with the air outlet of the conversion valve, the second air inlet of the conversion valve is in a closed state. At this time, the air duct of the ground brush, the air inlet pipe of the conversion valve, the air outlet of the conversion valve pipe and the air machine body inlet pipe are in a connected state. To the contrary, when the second air inlet of the conversion valve and the air outlet of the conversion valve are in a connected state, the first air inlet of the conversion valve is in closed state. At this time, the suction soft pipe, the air outlet of the conversion valve pipe and the air machine body inlet pipe are in a connected state.
When the upright vacuum cleaner provided with the conversion valve is used to clean the ground, the conversion valve is regulated firstly, so that the air duct of the ground brush, the air inlet pipe of the conversion valve, the air outlet of the conversion valve pipe and the air machine body inlet pipe are in a connected state. Then, the cleaner is powered on. Under the action of the internal suction of the cleaner, the dust or finely divided sundries adhering to the ground will, together with air, enter the dust collection chamber along the air inlet of the ground brush, the air duct of the ground brush and the air inlet pipe of the conversion valve (which is positioned as a whole on the outside of ground brush; in the specification of the Patent CN 200410002222.3, this pipe is named as “pressure head side suction soft pipe,” but is called as “air inlet pipe of the conversion valve” by some market attendants), the air outlet pipe of the conversion valve and the machine body air inlet duct. After being filtered through the filter screen in the dust collection chamber, the air is finally discharged from the cleaner body, while the dust and the finely divided sundries are remained in the dust collection chamber. In this process, the airflow direction in the air duct of the cleaner is shown as follows: air enters the air duct of the ground brush from the air inlet of the ground brush-->the air inlet pipe of the conversion valve (positioned on the outside of ground brush)-->the conversion valve-->the air outlet pipe of the conversion valve-->the air machine body inlet pipe-->the dust collection chamber-->the machine body air outlet duct-->a vacuum chamber-->the motor air exhaust pipe-->an exhaust outlet-->the atmosphere.
When the upright vacuum cleaner provided with the conversion valve is used to clean the other positions such as steps and table top, the conversion valve is regulated firstly, so that the suction soft pipe is communicated with the pipe which has entered the dust separating device, and at the same time, the air inlet of the conversion valve communicated with the air duct of the ground brush is closed. Then the motor is powered on. In the meanwhile, the nozzle of the suction soft pipe is allowed to contact with the position to be cleaned. Under the action of the internal suction of the cleaner, the dust or finely divided sundries adhering to the ground will, together with air, enter the conversion valve along the suction soft pipe, enter the dust-separating device through the air outlet of the conversion valve, and finally are deposited in the dust collecting barrel. In this process, the airflow direction in the air duct of the cleaner is shown as follows: air enters the suction soft pipe-->the conversion valve-->the air outlet pipe of the conversion valve-->the air machine body inlet pipe-->the dust collection chamber-->the machine body air outlet duct-->a motor vacuum chamber-->the motor exhaust pipe-->the exhaust outlet-->the atmosphere.
In a word, the said upright vacuum cleaner provided with suction soft pipe and conversion valve solves the problem of cleaning either the open ground or other positions such as hidden corners, steps and table tops. However, the upright vacuum cleaner with conversion valve in the prior art has deficiencies, in particular the unreasonable arrangement of pipes (air ducts). In other word, in the existing arrangement of air ducts, the airflow enters the air duct of the ground brush from the air inlet of ground brush, and then enters the dust collecting barrel through the air inlet pipe of the conversion valve (soft pipe or rigid pipe) provided on the outside of ground brush and by way of the conversion valve, the air outlet pipe of the conversion valve and the air machine body inlet pipe in turn. Since the soft pipe or hard pipe is provided on the outside of ground brush, such arrangement is not compact in overall structure and thus occupies more space; Furthermore, since the air inlet pipe of the conversion valve is exposed outside as a whole, it may be easily damaged and does not facilitate product packaging; In particular, since the air inlet pipe of the conversion valve is exposed as a whole on the outside of ground brush, the pipe collecting pipe is relatively longer, thus the energy loss of air in the process of flowing in the pipe is increased, leading to inadequate smoothness of air flow.